Process for agglomerating pulverulent material



Aug. 25, 1942 s. c. CARNEY 2,294,022

7 PROCESS FOR AGGLOMERATING PULVERULENT MATERIAL Filed June 12, 1939 2 Sheets-Sheet 1 Q m Lu T s2 -n V; LI L 2 l- Eu) k E 53 o INVENTOR S.C. CARNEY Patented Aug. 25, 1942 PROCESS FOR AGGLOMERATING PUl'aVER- T OFFICE- Samuel C, Carney, llartlesville, .okla assignorto Phillips Petroleum Company, a corporation of a Delaware Application June 12, 1939, Serial No. 278,753 1 r 5 Clahns. (01. 23-414) This invention relates to the art of transforming'thesdusty' light pulverulent material as produced, into free flowing, relatively dustle'ssjsmall.

aggregates with density of 20 pounds or more per cubic foot and is an improvement over myco-pending application, Serial No. 259,065, filed February 28, 1939.

'I'heobject of this invention is to increase the density and improve flow characteristics-of pulverulent' material, to cheapen andfacilitate storage and handling of the material and largely to eliminateits dusting character.

attrition. The mathematical laws governing growth of granules apply to this process. the sameas the co-pending process as to the inherent balance between the seed and pellet millin governing amount of seed. This process is also like the co-p'ending process and unlike'the Cabot and It is a further object to eliminate the dusting character of carbon black without interference with the step in rubber compoundingof thorough dispersion of the carbon black in the rubber batch. i r j The advantages of this process and apparatus over those of the prior art, including my co-pending application above mentioned are:

(1) Use of more stationary and less movable apparatus withnone of it being specially built;

(2) vLower construction cost;

(3) Less'horsepower to operate;

, (4) The moving apparatus is a material elevator of standard type which may be bought from a stock of several builders; v l (5) A muchfsmaller amount oifmaterial is in process which causes the reduction in horsepower and facilitates changing the operation from mav terial of one quality to another; v r

(6) The apparatus is readily emptied when changing from one quality of raw feed toanother; 7 (7) Operating adjustments for controlling the granule size and density when the rate of production of raw material changes are positive and simple. Thus the pelleting process may readily beoperated with variable throughput to match variable production rate, thus eliminating use of large storage tanks;

(8) Difllculty in other processes due to the coating of operating surfaces with material is eliminated.

(9) The apparatus is of such character and so or may not use added rubber balls to promote Huber processes in not passing through thedifii cult stage of converting raw feed plus fine seed into granules that will roll. co pending applicationadds around one pound of feed to one hundred pounds of free rolling,

dense material of substantially product size.

The difference between this and all other processes' including l my co-pending application, is this: all formerprocesses'caused the individual granules to 'rotate'relativeto each other while j the mass ofgranules remained relatively stationary, bymoving part (as in Cabots) or all of the apparatus (as in Hubers and my co-pending application) by use of horsepower. The rotating annulus of the co-pending application, when analyzed, may reasonably be said to be, a curved moving passageway in whiclrthe individual granules in a mass of them are caused to rotate relative'to each other by the contact of many of them with the moving walls of the passage, though the entire mass of granules remains relatively stationary.

Whereas, the others, in their action, resemble the rolling of a ball on the slope of a continuously moving treadmill, this process resembles the free rolling of a ball down a stationary slope, the ball then-being picked up at the. bottom, elevated to the top by use of 'power in a known device, and released to roll againdown'the same stationary slope.

' I 1 As my (Jo-pending applicationdifiered from the prior artby making the product itself the mechanism of the process, this process goes beyond it, by retainingthe productas the mechanism, but by moving that product, which is acting as the mechanism, instead of moving the apparatus.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying'drawings; forming apart of this specification, and in which like numerals are employed to designate like parts throughout the same, Y

Figure 1 shows diagrammatically a layout of the apparatus for carrying forward the process, Figure? shows a vertical view of the hoppers anddownflow-lines, Figure dsis a plan view .of that portion-of the apparatus-below the section line 3'3,

For it, too, like the seed mill Figure 4 is a plan view of that portion of the apparatus below the section line 4-4, and

Figure 5 is a plan view of that portion of the apparatus above the section line 5-5,

In the drawings, wherein for the purpose of iilustration, is shown a preferred embodiment of my invention, the numerals I and 2 represent 7 elevators for granule material, of known commercial type and may be, as will be discussed under operation, bucket elevators, or ofvertical helical screw type. The material being lifted by the elevator l passes by line 2, into line 4.which has the valve 5 for controlling flow, into the hopper 6. The numerals 1 and l'represent' two or more parallel down fiow lines through which material flows from hopper 5 into hopper 5. As controlled by valve ll, per Oby the spout Hi into the base of the elevator l and is re-elevated. Although all material from the hopper 9 is re-elevated, not all or it is delivered to the hopper by the valve l2 flows to the action or which it is separated into larger material flows from the hop- -8. A part, as controlledvibrating screen l3, by,

and smaller granules. The larger granules flow.

through line i4, thence to hopper 9.

The description except that it receives, as its raw material, granules of greater than product size which enter the seed mill cycle through line l5 and proceed by line ii to the hopper 9.

The apparatus to the right of the drawings constitutes the pellet mill in which the desired product is made. Here elevator 2 lifts material from its base and discharges itinto line H, then into line l8 controlled by valve l9 and thence into hopper 20. From the hopper the material into line l5 and back inthus far covers the cycle of the are longer than the direct distance between 5 and 5 and between 20 and and are preferably arranged in a very arranged in a wave-like course. Two down flow lines are disclosed from the hopper 6 to the hopper 9 and tour from the hopper 20 to the hopper 25. This number has been chosen arbitrarily but some number of lines greater than one is preferred and the flow then controlled by valves 31 and 28; and valves 39, 40,

The principle of the prior art is to take raw material as would enter by line 35, mix it=in some way with granules smaller than product size such as will flow in this process through line ii, and then by various forms of vigorous or gentle agitation assisted by compression, as by a tree roller, to cause this low density mass of extremely fine particles to agglomerate and finally begin to roll.

The process of this invention avoids this transition stage common to dry processes of the prior art by initially charging the apparatus as shown with commercial granular carbon black elsewhere produced. The charge is such in amount as to fill elevators I and 2, hoppers 5 and 20, the downflow lines I, 8, 2!, 22, 23 and 24 (not solidly, but with free flowing material with the elevators operating at normal speed) and so that withthe apparatus in normal motion a level as indicated exists in hoppers 9 and 25. The size and capacity of elevator 2 is so selected as to deliver from 50 to 100 times the weight of rawmaterial enterin flows downwardly through lines 2i, 22, 23 and 24 into the hopper 25. The material. leaves the bottom of the hopper 25 by the spout 26 and as controlled by valve 21, material flows to the base of the elevator 2 and is again elevated. Not all 01! the materialelevated by the elevator 2 flows to the hopper 20. A portion, as controlledby valve 28, flows into vibrating screen 29 which separates the fiow into three fractions. The traction of larger diameter than that of the desired product flowsby line i5 back to the seed mill. The intermediate fraction, which is also largest in volume, is the desired product or the entire operation and flows by line 30 to storage. That fraction with granule diameter smaller than the desired product flows by line 5! with part otthe flow from line 3| going into line [6 and thence to hopper 9 or the seed mill, though alternately it may be delivered through line 32 into hopper 25 of the pellet mill, these alternate points of delivery being controlled by valves 33 and 24. There is always delivered into hopper 25-through the lines 35 and 32, the fraction of smaller size from the seed mill as separated by the vibrating screen I3. The raw material, forexample carbon black from the producing plant, at its original low density, enters hopper 20 by line 35. The system will also operate if the material from line 36 enters the hues 2!, 22, 23 or 24, the hopper 25 or elevator 2. It is, however, preferred to introduce it into hopper 20 as shown in the drawingsr The down fiow lines I and 8, 2|, 22, 2 3 and 24 constitute a vital part in the novelty of the inper unit of time throughline'". Thesize and number of downflow pipes, 22, 23 and 24 are so selected that they will have a greater capacity for downflow than has elevator 2 for elevating. with the system initially charged, as described, and the elevator in operation, there is a very large closed cycle of. free flowing granular material of the desired density. To this large flow is continuously added through line 36 the raw material which is a much smaller stream, of weight on the order of 2 per cent of'that of the large cyclic stream of granular material. The angle of fall or the downflow tubes and the number or them in operation is so arranged that they flow loosely filled with the material in process. The rolling granules will agglomerate the fine raw material and increase in size. Meanwhile in the seed mill, which has a cyclic capacity less than one-fourth as great, similar granular material has been circulating without addition of raw feed to lubricate the granules and in the presence (if desired) or a small number or rubber balls. These conditions cause the opposite effect, that oi. attrition,

vention. They are preferably rubber tubes or hose made in the commercialmanner, but having a smooth rubber lining. They may, of course,

rather than growth. Valve I2 is partly opened, diverting a portion of the seed stream to screen [2. The smaller granules of this fraction fall through the sieve and are delivered by lines 25 and 22 into the product cycle, furnishing additional nuclei for agglomeration.

As the volume of material in the cycle served by elevator 2 increases the level in 25 will rise .and valve 28 is then partly opened, which may be done automatically, releasing to screen 29 an amount equal in weight to that or the raw material plus the seed. That part larger than the desired product flows by line l5 to supply raw material to the seed cycle. The intermediate, or product fraction, is removed as product and that part smaller than .desired product is either used direct as seed (valve 34 open, valve 32 closed) or by adjustment or these valves, is sent as a whole, or in part, to the seed cycle.

steep spiral or may merely be 4i, and42 aswillbe- ,more fully described under operation.

the continuous maintenance there of around 90' With addition oi new material to the seed cycle, the level in hopper 9 will rise. Valve I2 is adjusted either manually or automatically to maintain this level. These controls by levels at 25 and 9 insure that a'volume of seed will be :delivered to the product cycle equal to the volume delivered by the product cycle tothe seed cycle. There is thus an inherent balance between them,

because more seed will reduc th -amount flow-- ing through line I] whlchfin turn, will'reduce the amount of seed flowing through line 35. This control is based on th amount flowing through line II, but further and more delicate control oi the proportion of small and medium sizes within the product range is had by manipulation of valves 33 and 34.

Unlike the batch and lineal flow processes of the prior art, which take great pains to insure that each particle has received the same treatment, this closed cycle process follows the'analogy of chemical pmcessesQWhere statistical averages are used to govern processing. It is, for example, possible, though highly improbable, that a particle of raw material may enter the product after only one pass through elevator 2. But, if it does so, it must be attached to a granule within the product size. range which ha made many passes; g

The function or valve 11 is to adjust the ratio of cycle flow-to raw feed flow for control of density or finished product and also to adjust the" process to normal or abnormal variations in the per cent by weight of granules from 60 mesh up to around 14 mesh that makes it operative. It, has also been discovered that 14 meshis the practical limit of growth under the conditions described. This is thought to be due to the rm,

that the growth "is at the surface and tothegeometrical fact that a volume of granuleseachof diameter 3 units has but one-th'irdthe total 7 surface of that volume] eachwith, diameter unit, but each larger granule has fll'tlmesfthe' q volume of each smaller granule...- So it ispo'inted out that there is no reason ezcept" statistical probability why any individual; granule in the."

product cycle will escape from it thr'ough. valve a. But so large is the number-oi granules concerned, that the principlemay as it is ,4 I

in chemical plants.

. The reason for using rubber downflow promotes .rotais that their inner surface better tion in the flowing granules than does'metal and further carbon does not stick tothemi bothbe- 1 cause they are rubber "and because-they flex flow of raw material in line II, due to variations in the producing plant. Since elevator 2 can only lift what passes valve 21 and the principal supply to hopper 1' comes irom'elevator 2,the

. entire operation may be slowed down by throttlingyalve 21 and shutting oil one or more or the tubes 21, I2, 23 or 24. lncase orsuch an adjustment for lower through ut, the inherent balanc heretofore described would reduce the f volume ofseed supplied, but valve has the function in that as well as with full throughput, to reduce the severity of attrition in the seed cycle and thus to maintain constant the relative size of the seed supplied.

Unlike the prior art, whose processes are so severe and use so much power that they have .as an operating trouble. periods of too much seed of too small diameter 'which' isderived irom breakage in the process, it has been learned that by continuously introducing raw feed, intoa closed cycle of granules of full product size, the cycling granules are so lubricated that there is not enough breakage to make the process selfseeding, as is the prior art. But, by preparing the seed separately under control. the'present process can deliver a larger per cent than the prior art from the product screen 29 as finished product. Although the per cent larger than the desired product may be reduced by fitting a smaller" mesh screen in II. it is preferred to separate there and use as seed, material nearly or quite of the same maximum size as the product.

The granules; for example, of size between 28 mesh and 14 mesh which flow through line I! do not represent a loss of efiort but are an extremely important factor in promoting the rolling flow that gives rapid agglomeration. In, fact, they may logically be considered as the ball bearings 01' the process. v

The process here described is entirely inoperative if there were in the agglomerating cycle only the small seed or around 60 mesh and smaller of the prior art, together with the raw feed. It is desired quality, the new-feed admitted and the,

valves I and! 9 reopened.

There is an'advantage in principle; Relevators i and 2 be of the vertical helical screw type,

in that motion of the' granules relative to eachother is continued, and under somepressure, during this part of the cycle. This type of ele-' vator requires more power than the bucket type of equal capacity and must also run completely filled. with this type, the items shown as valves speed chang- H and I'I'b'ecome the controls of a ing device controlling the elevation.

Asa practical matter, the tubesl, 8.1L; 2!, 23 and 24 should be of reasonably small diameter ranging from 4 to 10 inches, a s'uflicient number" being used in parallel to carrythe required new.

The reason is to expose to the flow a sumcient rubber surface to impart the" necessary rotary motion. It is repeated that in this process it is absolutely essential that the large cyclic flow consist chiefly of granules whose size lies within the product range with, preferably, around '5 per cent of its size greater than the maximum product size.

A reasonable size for an operating unit is one to process 10 pounds per minute of raw'feed-or 14,400 pounds per day. Taking a cyclic ilow of to 1. which in most cases is more than required, gives a cycle flow in the pellet mill of 1,000 pounds per minute or 30 tons per hour.

Thirty feet is a practical. height for elevation,v

though this it not a critical matter. Power formula for bucket elevators is H. P. at the motor equals W so equals 1.63 H. P.

or 1,000 p0linds per minute to 30 foot head is 30,000 foot pounds per minute.

These horsepower figures are given because some-with whom the matter has been discussed more effective,

tive thing a 100 to 1 cycle ratio seems highly exceshour looks' like just too much sive and 30 tons per black to recycle. Butit is obvious that something which can be done by not at all unreasonable. With vertical screw type elevator, horsepower for a given flow is somewhat greater, duced by an amount more than compensating.

' Since the processes of the prior art' are ,self-.

seeding, there has grown in the trade the opinion that this-is an advantageous feature. Though it is not agreed that this is so in principle, because it involves a decrease in the extent of the operators control over the finer details of the product, it is agreed that for simplicity and reduced construction cost, one usually makessome the ideal principle. Having described the making of seed inapparatus wider compromise with separate control, it is now disclosed that the present process is, satisfactorily operative in ,a self-seeding manner by doing anything tothe operation which will promotebreakage of ,some

of the granulesr Whatever is done, should be of an adjustable character. Flowing the material over wire screen is known in the .art. 1-A controlled portion of the cycle stream may be diverted through any type of grinding mill and such a mill may itself be adjusted for;coarse or line grinding. i a This being a closed cycle process, time of residencetherefore becomes anessentlal point. In

computing this time, only zones of activity may be considered, residence in a hopper or in the cups of. an elevator increases actual but not effective, residence time. Time in a helical screw elevator does count continue their motion relative to each other.

..But although residence time in this'process is sider the cubic capacity of the-rubber tubes as the effective equivalent or the 90 degrees. of active volume in a rotating cylindrical annulus. These annuli have been figured on the conservaplant of the present process requires 8-6 inch inside, diameter rubber tubes of 35 foot length or 5 of 8-inch diameter and 32feet long.

Two propertiesofthese tubes must thereforebe. considered: i i I (1) Their volumetric capacity, which governs the statistical number of passes through them at any given ratio ofieed to cycle flow, and (2) Their flow capacity, for permitting the rolling down of the cyclic material handled by the elevator.

The volumetric capacity may be varied by means of the shutoff valves 39,. 40, ll, and 42 already shown in the disclosure, by cutting out of use one or more tubes. This givesan adjustable control over time of residence which is .not available in my co-pending application or in Hubers process.

It will be quite capacities of quantitative requirement. The more obscure qualitative requirementis much more important.

use o f--.,iust 2 horsepower is butthe recycle ratio; is re--' because there the granules it is conservative figuring to con-- basis of .supplying'feed equal to. 1/10 per plain that the sum of the flow the tubes in use must, at least, equal' that of the elevator but this;is a mere obvious That is, that the granules not slide. This desirable v plicated by the fact, usually overlooked, thatto must roll down, and

' roll a foot on. a plane surface without slippage,

granule Y has to make roughly 700 1' revolutions, while a 14 meshigranule will make it in about 85. A little thought will conceive ,any

a 100 mesh one thatlarge granules roll. more readily than small onesand that'small ones will'only roll at U all, at relatively low speed. One foot per second V a mile per hour, but for a small granule to make 700, or even 85, revo1uv tions per second while rolling afoot is clearly.

is only about of quite doubtful.

It is for this reason that the present process 4 works with granules of full product. size and larger always presentin all parts ofjthe apparatus.

rotaryeffect is almost ing.

be identified by the sense of hearing.

easily, be learned by an operator, many similar things in industry, judgment of this soundwill rapidly improve with experience.

When usingrubber tubes as described here, it 1 will alsobeplainthat their slope is a matter of a If their only function were to move the material downward, it would clearly.

prime importance.

be bestto 'arrangethem vertically. But it will be equally clear thatvertical arrangement is not.

the-best way to induce rolling- A steep spiral is the best arrangement but it is very, desirable that,

there be a means of adjustment of this spiral angle of slope so that the operator may be able to use the knowledge he gains by the experience of repeatedly I density. The slope must besuch as to separate the granules slightly in. space, thus giving them a short mean,,iree path. of travel relative to each other.v Myimpr ession of .what happens is that rotary motion ;is imparted to the mass chiefly by the larger sizes and the repeated collisionsbetween individuals, due totheir slight separation, serves, not only to compactthem but. also to communicate rotary motion. The sound, of a desirable condition is a sort or hiss, its tone quality rather than its. musical pltqh.,.being changed by change in the relative proportion of different sizes present. of amorphous feed, orof fine seed, de'adens the sound and this indicates slow agglomeration and low density. When only smallparticles are pres,

1 ent (100 to mesh, for example), soundcan scarcely be heard, even when particles are truly granular}, and the desirable rotarymotion is very diflicult to attain. This explainsthe long residence time required by a lineal flow: process. A rubbersurface better communicates rotation to the larger granules and even when usingthe relatively larger 8 ,inchbr 10 inch tubes mentioned, the rubber surface contacted is far greater than the metallic surfaces of map-1 paratus of the prior art. The spiral arrangement continuously changes the location of the bottoms of th tubes and'by holding the diam f eter of the spiral constant, its lineal nope will be rolling motion is comv 'But of course only. a very small proportion of the granules present aretinfoontact with" the wallsof the apparatus ,at anytime so the entirely due tothe tangent contact of granules with others which are rotat- By long and careful observationit has. been 1 testing the productior size and Too large a proportion,

erally be used, Thus a change of fourturns degrees and the vertical. By worklng in' the di-I-ii rection of lower angle of slope, the operatorjxcan the gear wheel 51 to turn the plate55.

' 65, 66 and 61 represent telescopic joints in addiconstant throughout its length, even when that of the product.

A stationary mast-dfisnclr V I ample, extends between thecenters of plates 50 to lengthen and this is the function of the teleof change in the length of tubes is sufilcient for all desirable adjustments in slope when the di-- ameter of the spiral is 2 feet and the distance between plates 50 and 55 is 30,1eet.

slope be changed by giving the-spiral a larger or smaller number of turns as by use of the adjusting mechanism here described or its equivalent.

No great change in the number of turns of-a 5 It is to be understood that the form of my inspiral is necessary to change its inclination vention, herewith shown and described, isto be within the range desirable in this process; This taken as a preferred example of the same, and may be seen from the fact that in a spiral with that various changes in the shape, size and arfeet length and 2 feet diameter, the angle of rangement of parts maybe resorted to without deslope when it has four turns is only about "45 de 10 parting from the spirit of my invention orthe scope of the subjoined claims. Having thus described my invention, I claim:

; v 1. The method or making dry granular carbon (and with larger diameter of the Jspir'al even black in a continuous closed cycle which cornless) will cover the range ,of' slope between 4511 5 prises continuously pouring a stream of tree flowing carbon granules into the top of a confined space enclosed by a sharply sloping surface, allowj ing; the said tree flowing carbon granules to fiow a 1 down the said confined space, removing the x21) stream of tree flowing carbon granules from the bottom 01 the confined space and returning it to the top of the confined space to complete the grees. Since the angle of repose oi the material" is around degrees, is lower than'willgem' make a reasonable lowering in the angleso'fj; pose of the product, though the size and char acter of seed has more influence on lquality Figures 2-5 show the details of" the down fiow tubes and also show an adjusting, arrangement to vary the slope of the. hose members. i The numeral represents-the. ,bottom' of the upper feed hopper 20 and 'is shown' in plan-in. Figure 5. It is of circularshapeand stationary, with the rubber'tubes =2lj,". 22,-. 23;and ,2l con-. nected to it by means oLballandsocket joints 5|, 52, 53 and 54, so that the-lco'nnection'is" free to rotate or to change its angular-direction A circular plate 55 is located atztl'ie top or the lower hopper. It is circular and ofthe same diameter as the plate 50 and it is so mounted that it may be rotated by a worm or'gear arrangement, The plate 55 has the gear 56- on its-outer "edge and the gear wheel 51 meshes with the gears 56 on the plate 55. A shaft 58 and wheel 59 connectwith 7 granules at the top of the confined space,""rernoving from thecyclic fiow as product an amount of added per cycle-being in the approximate ratio of 1:100 to the total carbon black inthe cyclic flow.

3 2. The method of making dry granular carbon ing carbon granules into the top otta confined The delivery ends of the hose areconnected into openings near the edge of the plate 55 also by movable joints 60, 6|, 62 and 63 except 54,

40 cycle, adding, raw carbon black to the stream of granules at the top of the confined space, removing from the cyclic fiow as product anamount of. granules equal to the weight of raw carbon black added to the cycle, the saldraw carbon tion to the ball and socket joints; ;'The telescopic black added per cycle being within the approxijoints 64, 65, 66 and .61 are, o f met'al but rubber lined and are capable of extension in length of about 4 feet. total carbon .black in the, cyclic fiow.

black in a continuous closed cycle which com- 0 prises continuously pouring a stream of free flowing carbon granules into the top of a confined spaceenclosed by a sharply sloping surface, the

and 55. Its function is solelyto align'the guides 69 and I0 whichare loosely'mounted onxthe sta-" tionary mast 68; free to rotate-about it or move i up and down. Their only function is'to guide stream of free flowing carbon granules comprisand space the rubber tubes and to lloldconstant 'ing approximately 90 per cent by weight 0! the diameter of the spiral inwhich [the tubesare 5 granules from mesh to 14 mesh in size, allowarranged. Any suitable number, d f such members 69 and 10 are used dependingonf the dis-' do wn the said confined space, removing the tance between 50 and 55. To the edges of 69 stream of free flowing carbon granules from the and .10 are loosely attached asiby a swivel joint, bottom of the confined space and returning it to clamps H and-12. By their attachment to the 60 the top oi! the confined space to complete the plurality of tubes, these clamps hold the spacing cycle, adding raw carbon black to the stream of members 69 and I0 in their relative positions. granules at the top of the confined space, remov- Plate 55 is arranged to .be rotated by the gear ing from the cyclic flow as product an amount of mechanism 56, 51, 58 and 59. Though probably granules equal to the weight of raw carbon black unnecessary, it is explained that such rotation added to the cycle, the said raw carbon black is not constant but is only a means for adjust added per cycle being within the approximate ment by the operator of the slope of the spiral. ratio limits of from 1:50 to 1:100 to the total car- To do this the operator may occasionally rotate bon black in the cyclic flow.

disc 55, for example, one-quarter or one-half 4. The method of making dry granular carbon revolution, either forward or backward. If he 70 blackinacontinuous closed cycle which comprises turns it in a direction to increase the number of turns in the spiral, the rubber members will have continuously pouring a stream of tree flowing carbon granules into the top of a confined space enclosed by a sharply sloping surface, allowing the said free flowing carbon granules to fiow down the said confined space, removing the stream of scopic joints 54, 65, 66 and 61 with which each of the tubes is equipped. It is noted that four feet cycle, adding raw carbon black to the stream oi'v granules equal to, the'weight ofraw" carbon black addedto the 'cycle, -the"said raw carbon black black in a' continuous closed cycle which'comprises continuously pouring a stream 'ot'Iree-flows'pace'enclosed by a sharply sloping surface, allowdownjthe said confined space, removing the" I the top of the confined space to complete the,

mate ratio limits of from 1:50. to 1:100 to the t *3. The method of making dry granular carbon ing the said free flowing carbon granules to fiow A cyclic flow as product tree flowing carbon granules from the bottomc'f the confined space and returning it to the tone! the confined space to complete the cycle, adding raw carbon black to the stream of granules at the top of the confined space, removing front-the an amount of granules equal to the weight of the raw carbon black added to the cycle, the said raw carbon black added per cycle being within the approximate ratio limits of from 1:50 to 1:100 to the total carbon black in the cyclic flow, and continuously adding a sum;- cient supply 01 granules of small diameter to balance the growth of the granules in cyclic flow from the addition of the rawcarbon black to maintain the average diameter or the granules retained in the process substantially constant.

5. The method 01' making dry granular carbon black in a continuous closed cycle which comprises continuously pouring a stream of free flowing carbon granules into the top ofa confined space enclosed by a sharply sloping surface, the stream of free flowing carbon granules compris- ;ing approximately 90 per cent -granu1esrpm 60 mesh to Mmesh in size; allowv .ing the said free flowing .carbon Branules to'flow down .-the said.- confined space, removing the. -stream ot Iree. flowinglcsrboni granulesirom-the ,-bott om ot the confined spa e audretnrning; it to by weights: of

the top of the conflned space-to complet'efthc .cycie, adding raw carbon black-to the 'streanio! 'granules at thejopvot; the space,.remov,- .ing mm the cyclic flow as product anamountpt :granules equal to the,weight.ot rawcarbonsblack added to the cycle, the said raw carbon black added, per cycle being-within the approximate ratio limits of from 1:50 to 1:100 to the,tota1 carbon black in the cyclic flow, and continuously adding a sufllcient supplyc! granules'ot small A diameter to balance thewgrowth ,0! the granules in cyclic flow Irom the addition of the raw carbon black to maintain the average diameter of the granulesretained in the process substantially constant. SAMUEL C. CARNEY. 

